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The bonding strength and LBE corrosion resistance of the Fe15Cr11Al2Si, Fe15Cr11Al0.5Y, and Fe15Cr11Al2Si0.5Y coatings heat‐treated at 500–650°C for 500 h were investigated. The results showed that the as‐deposited Fe15Cr11Al0.5Y coating has the strongest bonding strength with the F/M steel cladding tube compared with the Fe15Cr11Al2Si and Fe15Cr11Al2Si0.5Y coatings. Heat treatment deteriorates the bonding performance of the coatings, and obvious enrichment of Cr and Al elements appeared. The consumed Al element inside the heat‐treated coatings promotes the formation of Fe3O4 on the surface of the coatings after the corrosion test. The Y element can inhibit the enrichment of elements and the formation of Fe3O4. The bonding strength of the heat‐treated coatings can be improved after the corrosion test. The underlying mechanism of the evolution of microstructure and properties of the coatings after heat treatment and corrosion test was discussed. [ABSTRACT FROM AUTHOR]

Corrosion behavior of (Cr2/3Ti1/3)3AlC2 and Ti3AlC2 in static oxygen‐saturated liquid lead–bismuth eutectic (LBE) at 550°C and (Cr2/3Ti1/3)3AlC2 in static oxygen‐depleted LBE at 500°C were investigated. In oxygen‐saturated corrosion, the loose and porous corrosion layer consisting of (PbTiO3 + TiO2) was generated on the surface of Ti3AlC2. In contrast, (Cr2/3Ti1/3)3AlC2 formed the protective Cr2O3 layer with better corrosion resistance. Moreover, dissolution corrosion of (Cr2/3Ti1/3)3AlC2 in oxygen‐depleted corrosion was intensified without a protective oxide film. And impurity phase TiC on the surface also caused the decomposition of matrix, thus impairing corrosion resistance. [ABSTRACT FROM AUTHOR]

A CaO-MgO-Al2O3-SiO2 glass–ceramic coating was prepared by the slurry method and subsequent sintering to improve the corrosion resistance of 316L steel in liquid lead–bismuth eutectic alloy at high temperatures. The glass–ceramic coating, sintered at 884 °C, was dense and demonstrated strong adhesion to the substrate. It was composed of the crystalline phases diopside (CaMgSi2O6) and anorthite (CaAl2Si2O8) and had an average Vickers hardness of 595 HV, which was over three times that of 316L steel. After corrosion in an oxygen-saturated, static lead–bismuth eutectic alloy at 500 °C for 1000 h, the uncoated 316L experienced significant mass gain (0.04 g) due to severe oxidative corrosion, resulting in the formation of Fe3O4 and Pb2O on its surface. In contrast, the glass–ceramic-coated specimens showed a very small mass gain (0.0012 g) after corrosion. The coating maintained good thermal stability; its crystalline phase composition remained largely unchanged after the corrosion test. The glass–ceramic coating still exhibited dense microstructure and tightly adhered to the substrate after corrosion. There was no evident penetration of lead–bismuth into the coating, and no dissolution of the coating's elements into the lead–bismuth alloy was detected. These observations confirm that the glass–ceramic coating possessed superior corrosion resistance in liquid lead–bismuth eutectic environments. [ABSTRACT FROM AUTHOR]

CrN/TiSiN multilayer coatings deposited at 316 L substrate were selected to explore the effects of irradiation on LBE (Liquid Pb–Bi eutectic alloy) corrosion. The as-deposited and irradiated coatings were exposed in LBE. After exposure, all CrN/TiSiN coatings presented oxidation accompanied with PbBi penetration. Irradiated coatings revealed better corrosion resistance with thinner oxide layer and smaller penetration thickness. The largest decrement of 39 % in oxidation thickness was observed in CrN/TiSiN deposited with Ti 80 Si 20 under 150 V. The irradiation-decelerated LBE corrosion could be attributed to the rapidly formed protective oxide layer resulting from the irradiation defects which accelerated nucleation and diffusion process during oxides formation. The decelerated effect was relatively weak in coatings deposited with a bias voltage under 100 V, in which the decrement is under 10 %. The enhanced corrosion resistance was attributed to the quickly formed dense and continuous chromium oxide which rapidly formed due to the irradiation induced defects and acted as diffusion barrier to slow down LBE penetration. [ABSTRACT FROM AUTHOR]

The surface coating technology, encompassing ceramics, refractory materials, metallic alloys containing Al or Si, and multicomponent composites, presents a viable approach to improve the corrosion resistance of ferritic/martensitic (F/M) steels with (9–12) wt.% Cr in liquid lead-bismuth eutectic (LBE) environment. Among these coating materials, chromium (Cr) coating emerges as a particularly noteworthy option. This study specifically focused on depositing a 3 μm thick Cr coating on on T91 and SIMP steels using magnetron sputtering. Subsequently, the corrosion behavior of the Cr coating was investigated in LBE at temperatures of 600 °C and 700 °C. The results revealed that, after 300 h at 600 °C, T91 and SIMP steels formed oxide scales with approximately 32.6 μm and 19.3 μm thicknesses, respectively. At 700 °C for 140 h, these oxide scales increased to about 82.4 μm and 73.1 μm for T91 and SIMP steels, respectively. However, the application of a Cr coating resulted in the formation of a dense layer of chromium oxide with a thickness of 4–5 μm. This layer effectively impeded oxygen diffusion and Fe migration leading to a significant reduction in the corrosion rate of the steel. Notably, the Cr coating maintained secure attachment to the steel even after exposure to high-temperature LBE corrosion. These findings underscore the capacity of coating to markedly enhance the corrosion resistance of T91 and SIMP steels in high-temperature LBE environments, providing robust protection against the detrimental effects of challenging conditions. Consequently, Cr coating emerges as a promising solution for future fission nuclear reactors.

Seven FeCrAlY-Al2O3 nanoceramic composite coatings are deposited on F/M steel via plasma spraying and laser remelting. A systematic investigation is conducted to examine the dependence of microstructure, mechanical properties, and lead–bismuth eutectic (LBE) corrosion resistance on the nano-Al2O3 addition and different Cr and Al contents. With the increase in Al content in FeCrAlY, gradual refinement of the coating grains occurs. The addition of nano-Al2O3 promotes the elemental segregation and precipitation of the second phase. The nano-Al2O3 notably enhances the mechanical properties of the coatings that are primarily attributed to second-phase and fine-grain strengthening. After LBE corrosion tests, intergranular corrosion morphology could be observed, where the contents of Cr and Al significantly influence the corrosion behavior of the coatings at varying temperatures. [ABSTRACT FROM AUTHOR]

To improve the corrosion resistance of SIMP steel, we have investigated Si‐ion implantation and preoxidation effects on the corrosion behavior of SIMP steel samples, which have been in stagnant lead‐bismuth eutectic (LBE) with saturated oxygen at 550∘ $55{0}^{\circ }$C for 1000 h. It was found that increasing Si content on the surface did not improve corrosion resistance performance. By contrast, the preoxidized sample demonstrated high resistance to LBE corrosion due to the presence of a thin Cr‐enriched oxide layer. [ABSTRACT FROM AUTHOR]

In the design of the spallation target of CiADS, T91 steel was selected for the most critical component, the beam window. A Si-modified martensitic steel (SIMP) has been currently developed, which has better corrosion resistance and is planning to replace T91 as a material of beam window in the future. In order to assess the effect of irradiation damage on the microstructure evolution and corrosion behavior of the SIMP, the pre-irradiated samples with irradiation doses from 5 × 1015 to 3 × 1017 He/cm2 exposed in static lead-bismuth eutectic (LBE) with saturated oxygen at 350 °C for 4000 h were investigated. Results show that pre-irradiation neither change the double-layer structure of the oxide layer nor significantly affect the corrosion rate. This may be due to the slow diffusion of elements at low temperatures, and the low irradiation dose not reaching the threshold for triggering accelerated corrosion. [ABSTRACT FROM AUTHOR]

The microstructure and LBE corrosion behavior of the irradiated (up to 110 dpa) Fe15Cr11Al0.5Y coatings were investigated. The surface roughness and hardness increased with the irradiation dose. Irradiation induces grain growth, and the grown grains contain many dislocations, but no segregation and voids. Irradiation accelerates the corrosion rate of the coating, and the irradiated coatings suffer from serious inward non-uniform growth of the Al 2 O 3 layer. The reaction of Al 2 O 3 with PbO promoted the formation of the outermost PbAl 2 O 4 of the irradiated coating. A "competitive mechanism" was proposed to explain the evolution of the corrosion behavior of the irradiated coatings. • The FeCrAlY coating irradiated with a damage level of up to 110 dpa. • Surface roughness and hardness increased with irradiation damage level. • Irradiation accelerates the corrosion rates of the FeCrAlY coating. • The reaction between Al 2 O 3 and PbO promoted the formation of PbAl 2 O 4. • A "competitive mechanism" was proposed to explain the evolution of corrosion behavior. [ABSTRACT FROM AUTHOR]

The high-temperature lead-bismuth eutectic (LBE) corrosion resistance and ring compression performance of the Fe15Cr11Al2Si, Fe15Cr11Al0.5Y, and Fe15Cr11Al2Si0.5Y coatings were investigated. Even if the corrosion test temperature reaches 800 °C, all these coatings can effectively protect the steel cladding tube. After the corrosion test temperature exceeded 660 °C, an obvious Al-rich oxide layer was formed on the surface of the coating, and Al element enrichment occurred at the interface between the coating and the substrate. After the corrosion test at 800 °C, holes appeared in the thick interface layer of the Fe15Cr11Al2Si0.5Y coating. The Fe15Cr11Al2Si coating cracked after the ring compression test with a deformation rate of 3%, and the coating peeled off after the deformation rate reached 5%. When the deformation rate reached 5%, there was still no cracking in the Fe15Cr11Al0.5Y coating. When the deformation rate reached 30%, the coating cracked, but the cracked coating was still tightly bonded with the substrate. The Fe15Cr11Al2Si0.5Y coating has the worst compression performance, even if the deformation rate is 1%, the coating still peels off obviously. The underlying mechanism for the evolution of corrosion resistance and compression performance was discussed.

MAX phases are promising candidate structural materials for lead-cooled fast reactors (LFRs) and accelerator-driven sub-critical systems (ADSs) due to their excellent corrosion resistance in liquid LBE. In this work, one of the typical MAX phases, Ti3SiC2, was exposed to the flowing LBE with a saturated oxygen concentration at 500 °C for up to 3000 h. The corrosion behaviors, including the evolution of the corrosion layer, mechanical properties and wettability, were evaluated via X-ray diffraction, a scanning electron microscope equipped with an energy-dispersive X-ray, a microhardness test and contact angle measurement. The results reveal that a corrosion structure with a duplex layer was formed on the sample surfaces. The outer layer was a diffusion layer, which always remained thin (<3 μm) during the whole test due to the erosion effect caused by the flowing LBE. The inner layer was the stable protective oxide layer, and its thickness increased with exposure time. The growth of the corrosion structure improved the microhardness and reduced the wettability with regard to LBE, which was beneficial to inhibiting further surface corrosion of Ti3SiC2. [ABSTRACT FROM AUTHOR]

[Display omitted] • TiAl second phase inhibiting elemental diffusion at grain boundaries to resist LBE corrosion. • AlTi 0.75 CrFe shows the best performance with the thinnest OL after LBE corrosion. • Increased Ti in HEA coating leads to finer grains and better corrosion resistance. High-entropy alloy (HEA), when used as coating materials for structural steel in lead–bismuth eutectic (LBE) nuclear reactor, faces severe dissolution corrosion due to the diffusion of their constituents along grain boundaries. In order to mitigate dissolution corrosion, a method to enhance the LBE corrosion resistance of HEA is proposed by utilizing a second phase to inhibit elemental diffusion at grain boundaries. Herein, we used the laser cladding technique to prepare a series of biphase AlTi x CrFe HEA coating with a body-centered cubic primary phase and a TiAl second phase. During the LBE corrosion process, a single-layer oxide layer (OL) formed on the HEA coating surface, and meanwhile there existed an internal oxidation zone (IOZ) formed beneath the single-layer OL at AlTi x CrFe HEA coating interface, which gradually converted into the single-layer OL as the corrosion time prolonged. After 2000 h of corrosion, AlTi 0.75 CrFe HEA coating exhibited the lowest OL thickness (8.1 μm) and oxidation rate (0.065 μm2/h) because Al, Ti, and Cr acted as protective elements, rapidly forming a protective OL on the surface. Meanwhile, the presence of TiAl second phase at the grain boundaries impeded the mobility of elements, which improved the dissolution corrosion resistance and diminished its destructive impact on the protective OL. [ABSTRACT FROM AUTHOR]

For lead‐cooled fast reactors and accelerator‐driven subcritical systems, the surface corrosion behavior of candidate structural materials in lead–bismuth eutectic (LBE) is a key issue, which determines whether the material is applicable. The candidate materials of two typical MAX phases, Ti3SiC2 and Ti3AlC2, were immersed in static LBE with saturated oxygen concentration at 500°C for up to 3000 h. The corrosion behaviors of Ti3SiC2 and Ti3AlC2 were analyzed by scanning electron microscope, energy‐dispersive X‐ray, X‐ray diffraction, and Raman spectra. The experimental results showed that elements interdiffusion between LBE and sample matrix occurred on both Ti3SiC2 and Ti3AlC2 surfaces, which led to the formation of the diffusion layer. The dominant component of the diffusion layer is PbTiO3, which makes the corroded surface fragile in a stress environment. Besides, there were differences in structures of corroded sample surfaces between Ti3SiC2 and Ti3AlC2. The corrosion layer of Ti3SiC2 consisted of two layers, while only one single layer formed on Ti3AlC2 surfaces. The stable oxide layer consisting of SiO2 and TiO2 can protect Ti3SiC2 samples from further LBE corrosion and maintain the integrity of the surfaces. For Ti3AlC2 samples, it is hard to form a continuous Al2O3 protective layer, thus no stable oxide layer was detected on the corroded surfaces. Compared with Ti3AlC2, Ti3SiC2 showed better corrosion resistance in LBE. [ABSTRACT FROM AUTHOR]

The lead-cooled fast reactor (LFR) is one of six reactor concepts selected in the Generation IV Technology Roadmap and is perhaps the first to be applied commercially. Because the heavy liquid metal coolant has a severe corrosion effect on the core structure, the compatibility of the heavy liquid metal coolant and structural materials is recognized as a key limitation in the design and application of the LFR. Corrosion by heavy liquid metals such as liquid lead or lead–bismuth eutectic (LBE) is a physical or physical–chemical process involving surface oxidation, dissolution of material constituents, erosion corrosion, and fretting corrosion. Corrosion by heavy liquid metal can change the microstructure, composition, and surface morphology of structural materials, which will affect their mechanical and physical properties and lead to system failure. Currently, LFR research institutes are devoting great effort to the research and development of structural materials with good high-temperature mechanical properties and excellent corrosion and irradiation resistances. In this study, a series of experiments and analyses were performed on self-developed 11Cr−1Si ferritic/martensitic (F/M) steel, including heat treatment tests, mechanical tests, corrosion tests in static lead-bismuth eutectic (LBE), and slow strain-rate tests (SSRT) in LBE. The heat treatment results show that 11Cr−1Si steel obtains a good combination of high strength and toughness after quenching at 950 ℃ and tempering at 750 ℃. 11Cr−1Si steel was found to have good LBE corrosion resistance after exposure in static LBE for 3368 h, with a sufficiently low oxidation rate and a continuous and compact surface oxide layer, which protect the base metal of 11Cr−1Si from LBE penetration. The SSRT results show that the ductility of 11Cr−1Si in contact with LBE is sensitive to temperature, with loss of ductility observed at 350 ℃ and 400 ℃, but not at 450 ℃.

The corrosion characteristics of 12Cr2W2Mn Ferritic/martensitic (F/M) steel before and after Au-ions irradiation in static lead–bismuth eutectic (LBE) have been investigated at 400 °C for 100 h. The results show that the samples without irradiation have many unequal size Fe3O4 particles and little Cr-rich oxide after LBE corrosion test, and the thickness of corrosion layer is 4.4 μm. The irradiation samples display plenty compact triangular (Fe,Cr)3O4 and some Cr-rich oxide, and the thickness of corrosion layer is 4.4 μm with some cracks. Au-ions irradiation enahnced the LBE corrosion of F/M steel, which could be attributed to the irradiation defects provide diffusion path of O atoms in liquid LBE. A schematic model was presented to understand the effect of irradiation damage on LBE corrosion behavior of F/M steel.

MAX phase ceramics attract increased attention for lead-cooled fast reactors due to their promising compatibility with lead-bismuth eutectic (LBE). This work systematically investigates the corrosion behaviors of five Ti 3 Al 1−x Si x C 2 MAXs with Al/Si complex A component in static LBE at 550 ºC up to 3000 h. Based on the lattice structure, mechanical properties, surface morphologies, and elemental composition during corrosion, a synergism of Al and Si during oxidation and diffusion is found, which contributes to a continuous and well-attached Al 2 O 3 layer with improved LBE corrosion resistance. Therefore, the multi-element design will bring a broad space for the applications of MAX ceramics. • Ti3Al1−xSixC2 presents an enhanced corrosion resistance in Pb-Bi eutectic. • The continuous Al2O3 layer is proven as the crucial anti-corrosion species. • Moderate amount of Si is beneficial for a thin and continuous Al2O3 layer. [ABSTRACT FROM AUTHOR]

Liquid metal corrosion has become a critical issue in lead-cooled fast reactor when the steel encounters lead–bismuth eutectic (LBE). Although various coatings applied in LBE have garnered interest from many researchers, there are few reports on the compatibility of chrome carbide or chromium nitride coatings in LBE. Thus, Cr carbide and Cr-nitride coatings with thicknesses of 80 μm were prepared on 316H stainless steel (SS) to investigate the corrosion behavior in contact with static liquid LBE at 550 °C for 25, 76, and 207 h. These coatings were synthesized via pack chromizing and subsequent gas nitriding. The results showed that a distinct LBE penetration layer appeared on the surface of the as-received 316H SS after exposure to LBE. Pack-chromized coating and pack-chromized + gas nitride coating did not undergo obvious consumption in LBE in the early stages. Cracks in the pack-chromized coating promoted the preferential diffusion of oxygen and Pb Bi. The Cr in the pack-chromized + gas nitride coating slightly diffused outward to combine with oxygen to form Cr-oxide scale on the coating surface. These coatings act as a barrier to LBE corrosion, making the surface of the coating impermeable to LBE. • Cr atoms absorbed by 316 H SS during the chromizing treatment dissolved within the Fe in the substrate and formed a solid solution of Cr in α-Fe. • The outermost layer of the pack-chromized sample consists of Cr 23 C 6 (about 5 μm), with α-Fe (substrate) underneath. • Cr 2 N and CrN generated during the gas nitriding treatment is diffusely distributed inside the α-Fe phase. • The larger grain size of Cr 23 C 6 in pack-chromized coating is more prone to defects as cracks and pores in the normal oxide layer. [ABSTRACT FROM AUTHOR]

FeCrAl(Y) coatings have excellent LBE corrosion resistance, but their actual performance could be predicted more accurately by simultaneous irradiation and corrosion experiments. Here two kinds of FeCrAl coatings were corroded at 550 ℃ while subjected to simultaneous proton irradiation. The results showed that irradiation did not change the three-layered structure of the surface oxide scale. Compared with the FeCrAl coating, the FeCrAlY coating has better corrosion resistance in the unirradiated-corroded area, while undergoing more serious accelerated corrosion in the simultaneous irradiation and corrosion area. The corrosion mechanism was discussed in detail and a corrosion model was proposed. • The FeCrAlY coating has better corrosion resistance in the unirradiated-corroded area. • The FeCrAlY coating undergoes more serious accelerated corrosion in the simultaneous irradiation and corrosion area. • The Al-rich segregation and holes appeared at the grain boundary of the coating. • The elemental diffusion accelerated by irradiation defects deteriorates the performance of the coating. [ABSTRACT FROM AUTHOR]

Three kinds of FeCrAlSi coatings with different Si contents were prepared by the magnetron sputtering method, and the LBE corrosion resistance was investigated at 500 °C, 550 °C, and 600 °C for 1000 h. The results showed that the corroded coatings present a shiny surface (circle morphology). The increase of Si content promotes the thinning of the total oxide scale and thickening of the Al 2 O 3 layer. The Si-rich layer appeared between the FeAl 2 O 4 and the Fe(Cr,Al) 2 O 4 spinel layers. The corrosion mechanism is discussed in detail, and a corrosion model based on the TEM analysis of the coatings corroded at 600 °C is proposed. • The increase in Si content promotes the thinning of the oxide scale. • Si-rich strip layer appeared inside the spinel layers. • The difference in O content promotes the formation of the Al 2 O 3 layer inside the corroded coating. • The Si content required to obtain outstanding performance is at least 1.8 wt%. [ABSTRACT FROM AUTHOR]

• Anti-LBE corrosion FeCrAlW x HEA coating was prepared by selective laser melting. • FeCrAlW 0.75 HEA coating has outstanding LBE corrosion resistance. • LBE corrosion protection of FeCrAlW 0.75 HEA coating and its mechanism analysis. • FeCrAlW 0.75 HEA coating exhibits good mechanical properties after LBE corrosion. The use of ferritic/martensitic (F/M) steel as a container material for liquid lead–bismuth eutectic (LBE) presents several challenges owing to the complex and diverse types of LBE corrosion, including dissolution corrosion and oxidation corrosion. This paper proposes a novel strategy to address these challenges, based on the optimization of the design and composition of FeCrAlW x high-entropy alloy (HEA) coating. The objective is to simultaneously enhance the resistance of F/M steel to both dissolution corrosion and oxidation corrosion. Following LBE corrosion, the surface of the coating exhibits oxide layers consisting of an outer oxide layer (OOL, composed of Fe oxides) and an inner oxide layer (IOL, composed of Al 2 O 3 and Cr 2 O 3). Among the tested samples, FeCrAlW 0.75 HEA coating exhibits the thinnest OOL and IOL layers when subjected to LBE corrosion over different durations, demonstrating superior resistance against LBE corrosion. The incorporation of W in the coating increases the covalency of the HEA coating, thereby improving the bonding strength. In addition, it decreases the adsorption energy of Pb and Bi on the surface, thereby effectively limiting the mutual diffusion of the coating elements and Pb and Bi and inhibiting dissolution corrosion. Furthermore, the IOL formed by Al and Cr exhibits protective properties and improves the oxidation corrosion resistance of the coating. These effects are further enhanced by the high adsorption capacity of the FeCrAlW 0.75 HEA coating to O, which helps accelerate the formation of the IOL. Additionally, the FeCrAlW 0.75 HEA coating retains satisfactory mechanical properties after being subjected to LBE corrosion for 2000 h, with the Hv, E, Hv / E, and Hv 3/ E 2 values being 6.92 GPa, 197.2 GPa, 0.0351, and 0.00852, respectively. "For Table of Contents Use Only." [Display omitted] [ABSTRACT FROM AUTHOR]

The synergistic effect of irradiation and Lead Bismuth Eutectic (LBE) corrosion on structural materials is of vital importance for the research and development of future lead cooled nuclear energy systems. A Heavy Liquid Metal and Irradiation Facility (HLMIF) was therefore designed and constructed at National Laboratory of Heavy ion Accelerator in Lanzhou. The facility provides a capability to use heavy ions in situ to irradiate a specimen in simultaneous contact with flowing LBE. In this experiment, a thin disc of material serves as both a beam window isolating high temperature LBE loop from the accelerator, and as a specimen irradiated by ions, allowing studying the synergistic effect. The facility has been successfully tested by using 247 MeV Ar ion beam to irradiate a sample of SIMP steel simultaneously exposed to flowing LBE at 350 °C. The initial experiment was continuously conducted for 92h without any accident or unexpected failures. The preliminary results showed that the LBE corrosion of SIMP steel was obviously accelerated by ion irradiation even at low damage. [ABSTRACT FROM AUTHOR]

The effect of shot peening on microstructure and corrosion of 15–15Ti austenitic steel in liquid LBE at 550 ℃ was investigated. The nanocrystallization and preferential recrystallization were observed, improving the resistance to corrosion and intergranular cracking in LBE. The intensive grain boundaries and dislocations on steel surface improved the compactness and adhesion of the formed oxide scale, efficiently preventing LBE penetration into steel. The Cr-rich oxide formed in boundaries of the recrystallized grains is Fe-Cr spinel with porous structure, it significantly prohibited the counter diffusion of elements, suppressing the growth of outer magnetite layer and inner transgranular oxide. • The corrosion resistance of 15–15Ti steel in LBE is improved by shot peening. • The magnetite layer formed in shot-peened steel presents better stability and protection. • The preferential recrystallization occurs in subsurface of shot-peened steel. • The Cr-rich spinel formed in the boundaries of recrystallized grains is porous in structure. [ABSTRACT FROM AUTHOR]

Fe x Al/Al 2 O 3 (x ≈ 3, 2, 1, 0.5) coatings are prepared on steel to investigate their potential for application in lead-cooled fast reactors through mechanical tests and corrosion tests. The results show that the increase of Al content in the transition layer changes its structure (ordered transition from α - Fe to B2), which enhances the hardness, brittleness, and wear properties of the coating, but decreases the bonding of the coating to the substrate (tough-brittle transition). In addition, Fe x Al/Al 2 O 3 coatings have excellent resistance to lead-bismuth eutectic. The Al content in the transition layer has an almost negligible effect on the lead-bismuth eutectic corrosion properties but increases the segregation of the Al element in the substrate. The segregations are mainly hexagonal and cubic AlN, and their generation mechanisms are elucidated in detail. [ABSTRACT FROM AUTHOR]

The corrosion behavior of the FeCrAl coating with different Cr and Al contents before and after Au-ions irradiation was investigated in static LBE. The grain of the irradiated coating changed from nanocrystal to large columnar crystal. The irradiation accelerated the LBE corrosion rate, and the oxide scale changed from three layers to four layers. Nodular corrosion was found in the irradiated FeCrAl coating. The change of Cr and Al contents has a remarkable effect on the corrosion behavior of the irradiated coatings. • Large-sized columnar crystals appeared in the irradiated FeCrAl coatings. • Irradiation in the corrosion process is related to radiation-enhanced diffusion. • The oxide scale changed from three layers to four layers. • Nodular corrosion was found in the irradiated FeCrAl coating. • The change of Cr and Al contents affects the irradiation behavior of the irradiated coatings. [ABSTRACT FROM AUTHOR]

The effect of Au-ion irradiation on the morphology, microstructure and lead-bismuth eutectic (LBE) corrosion behavior of refractory TiNbZrMoV high-entropy alloy coating was investigated. After irradiation, the surfaces of coatings were smoothened, and crystalline phase was formed in the coatings. After LBE corrosion at 650 °C, the irradiated samples presented a triple layer (interface Fe-Cr spinel, coating and surface Fe-oxide layer) consistent with the pristine sample, and the coating still maintained the low-consumption characteristic. Irradiation accelerated LBE corrosion, which could be attributed to the formation of grain boundary and defects that provided more diffusion channels for atoms. [ABSTRACT FROM AUTHOR]

The corrosion mechanism of 15–15Ti and 316Ti austenitic stainless steels exposed to liquid lead-bismuth eutectic (LBE) at 550 ℃ with dissolved oxygen 5 × 10−7 mass% was investigated. The oxides formed on steels have a dual- or triplex-layered structure. The higher content of Cr in oxides, the better inhibiting effect on Ni diffusion. The local dissolution attack left a Ni-rich recrystallization area with fcc -phase fine grains. The preferential intergranular oxidation (PIO) in random GBs of 15–15Ti induced intergranular cracking while the annealing twin boundaries were more resistant to crack. The 316Ti with smaller grains presented higher resistance to corrosion and intergranular cracking. • The intergranular oxidation in 15–15Ti steel can induce the intergranular cracking. • The annealing twin boundaries presents higher resistance to intergranular cracking. • The TiN precipitates promote local preferential oxidation and cracking of oxide. • The Pb can preferentially diffuse along grain boundaries compared to the Bi. • The dissolution attack leaves a confined Ni-rich area with fcc phase fine grains. [ABSTRACT FROM AUTHOR]

Sixteen kinds of FeCrAl coatings with different Cr and Al contents were prepared by the magnetron sputtering method, and the thermal shock resistance and static lead‑bismuth eutectic (LBE) corrosion behavior (500– 650 °C for 1000 h) were investigated. The results show that the coating with poor thermal shock resistance could also peel off during the corrosion test, and the corrosion resistance of the coating is strongly related to the Cr and Al composition. A relatively high Al content could be required for the FeCrAl coatings to maintain outstanding performance, which is different from the traditional design of the FeCrAl bulk alloys. • Grain refinement and left shift of diffraction peak appeared with the increase of Al content. • The coatings with relatively poor thermal shock resistance could also peel off after LBE corrosion experiments. • The critical Al content required for the FeCrAl coatings is decreased with the increase of Cr content. • Circle morphology and continuous Al-rich oxide scale formed on the coating surface after the corrosion experiment. • The critical Al content for the FeCrAl coatings should be >8 wt%. [ABSTRACT FROM AUTHOR]

The corrosion behavior of three stainless steels (316L, Alkrothal 720 and Kanthal-APM) in static LBE with oxygen concentration of 10 −5 wt% at temperatures of 700 °C for 230 h and 800 °C for 360 h was studied. The steel surface morphology of the oxide scales formed was investigated by SEM, XRD and Raman spectroscopy and the cross-section by SEM and EDX. A transitional inner-layer of Fe–Cr–Al oxides was found at the substrate interface and an Al-oxide outer layer on the Fe–Cr–Al alloys. Fast growing non-protective oxide scale with underlying dissolution was observed on the 316L alloy. [ABSTRACT FROM AUTHOR]

The effect of the Si addition content ranging from 3.3 to 9.1 at.% on the microstructure, mechanical properties and LBE corrosion behaviour of AlCrFeMoTiSi x HEA coatings was investigated. The coatings still maintained an amorphous structure, and their mechanical properties were improved. The Si addition greatly contributed to the enhancement of the LBE corrosion resistance of the coatings, which could be attributed to the formation of a more continuous and protective Cr 2 O 3 and Al 2 O 3 layer. However, the improved efficiency was related to the Si addition content, with an oxidation process model put forwards to well explain this phenomenon. • The amorphous AlCrFeMoTiSi x HEA (x = 0.03, 0.06 and 0.09) coatings were prepared successfully. • The Si addition improved mechanical properties of the AlCrFeMoTiSi x coatings. • The Si addition gave a great contribution to the enhancement of LBE corrosion resistance of the coatings. • The improved efficiency was related to the Si addition content. [ABSTRACT FROM AUTHOR]

Abstract: The performance of structural materials in lead or lead-bismuth eutectic (LBE) systems is evaluated. The materials evaluated included several US steels (austenitic steel [316L], carbon steels [F-22, Fe-Si], ferritic/martensitic steels [HT-9 and 410]), and several experimental Fe-Si-Cr alloys that were expected to demonstrate corrosion resistance. The materials were exposed in either a dynamic corrosion cell for periods from 100 to 1,000 h at temperatures of 400, 500, 600 and 700°C, depending on material and exposure location. Weight change and optical SEM or X-ray analysis of the specimen were used to characterize oxide film thickness, corrosion depth, microstructure, and composition changes. The tests conducted with stainless steels (410, 316L and HT-9) produced mass transfer of elements (e.g., Ni and Cr) into the LBE, resulting in degradation of the material. With Fe-Si alloys a Si rich layer (as SiO2) is formed on the surface during exposure to LBE from the selective dissolution of Fe. [Copyright &y& Elsevier]

The performance of structural materials in lead or lead-bismuth eutectic (LBE) systems is evaluated. The materials evaluated included refractory metals (W, Mo, and Ta), several U.S. steels [austenitic steel (316L), carbon steels (F-22, Fe-Si), ferritic/martensitic steels (HT-9 and 410)], and several experimental Fe-Si-Cr alloys that were expected to demonstrate corrosion resistance. The materials were exposed in either an LBE rotating electrode or a dynamic corrosion cell for periods from 100 to 1000 h at temperatures of 400, 500, 600, and 700°C, depending on material and exposure location. Weight change and optical scanning electron microscopy or X-ray analysis of the specimen were used to characterize oxide film thickness, corrosion depth, microstructure, and composition changes. The results of corrosion tests validate the excellent resistance of refractory metals (W, Ta, and Mo) to LBE corrosion. The tests conducted with stainless steels (410, 316L, and HT-9) produced mass transfer of elements (e.g., Ni and Cr) into the LBE, resulting in degradation of the material. With Fe-Si alloys a Si-rich layer (as Si02) is formed on the surface during exposure to LBE from the selective dissolution of Fe. [ABSTRACT FROM AUTHOR]

The effect of Au-ions irradiation with different damage doses from 10 to 90 dpa on mechanical properties and LBE corrosion behavior of AlCrFeMoTi HEA coating was investigated. The fracture toughness and the interface bonding strength had been improved after irradiation. The Au-ions irradiation decelerated LBE corrosion rate of coating at low damage dose, which could be attributed to the formation of a more continuous Cr 2 O 3 layer adjacent to the coating surface. However, the element diffusion was intensified and the Cr 2 O 3 layer became more thick and porous at high damage dose, which resulted in the acceleration of LBE corrosion. • The amorphous AlCrFeMoTi HEA coatings were irradiated by Au-ions and then exposed to liquid LBE. • The fracture toughness and the interface bonding strength have been improved after Au-ions irradiation. • The Au-ions irradiation decelerated overall corrosion of coating at low irradiation damage dose. [ABSTRACT FROM AUTHOR]

High performance LBE corrosion-resistant- materials have great potential for application in the future 4th generation nuclear reactor. In this paper, LBE corrosion behavior of AlTiN coating was carefully evaluated at typical working temperatures of nuclear reactor. The coating was synthesized by cathodic arc ion plating on 316L stainless steel (SS) substrates and subjected to LBE corrosion at 550 and 600 °C for 500 h. We used SEM, AFM, EDS, XRD and Raman to carefully characterize the microstructure evolutions of the coating. The results show that the coating could effectively enhance the LBE corrosion resistance of the SS at both 550 and 600 °C. The excellent corrosion resistance performance could be attributed to the in-situ formation of a dense oxide layer on the coating surface, which mainly consists of TiO 2 (Anatase and Rutile) and γ-Al 2 O 3 phases with slow growth rate and stable structure. In addition, the dense oxide layer of the coating exhibits a lower wettability to liquid LBE metal because of the nano-scale surface morphology, which further enhance the corrosion resistance. While for bare SS substrate, porous oxide was formed after LBE corrosion. These results suggested that AlTiN coating is a promising material for improving the LBE corrosion-resistant performance of the component used in the future nuclear reactor. A AlTiN coating exhibited excellent corrosion resistance against liquid LBE at temperatures of 550–600 °C, which could be attributed to the in-situ formation of a dense oxide layer with nano-scale structure on the coating surface. Image 1 • Thick AlTiN coatings were deposited on stainless steel for LBE corrosion test. • The coating exhibited excellent corrosion resistance at 550–600 °C. • Dense oxide layer with stable structure was formed on the coating surface. • Oxide layer with nano-scale surface structures showed low-wettability to liquid LBE. [ABSTRACT FROM AUTHOR]